Prevailing views on attention consider it to be dichotomous, as either stimulus-driven or goal-driven. Previous research suggests that both forms correspond to distinct, independent functional systems. Notably, findings highlight how these systems combine in an additive manner for task performance. At the neural level, however, the independence of stimulus- and goal-driven orienting systems remains unclear. The current study tested whether we would observe an additive or interactive pattern for the combined influence of stimulus- and goal-driven attention across neural markers of attentional processing. Participants (N=24) completed stimulus-driven, goal-driven, and combined attention spatial cueing tasks while we recorded 64 channels electroencephalography (EEG). We evaluated the isolated and combined influence of these attention systems over the P1, a positive, posterior deflection of the EEG signal that peaks around 100–130ms post-target, and the N2pc, a posterior component occurring 200–300ms post-target with a larger negative contralateral deflection compared to the ipsilateral side. Ample research supports the prominent influence of attention on the P1 and N2pc, making them ideal candidates to evaluate the interaction of stimulus- and goal-driven attention at the level of sensory processing. We analyzed behavioral and EEG data via hierarchical regression models and tested the model comprising the interaction between attention systems (alternate hypothesis) against the model solely comprising their main effects (null hypothesis). Behaviourally, we replicated previous findings supporting an additive pattern between stimulus- and goal-driven attention, as their interaction was not reliable. Bayes factor analysis conveyed strong support in favor of the null hypothesis. Conversely, at the neural level, we saw a reliable interaction between stimulus- and goal-driven attention across both the P1 and N2Pc. Hence, while both systems influence early sensory processing in an interactive manner, this particular effect does not emerge behaviourally. These results highlight the nuanced dynamics of attentional processing at the level of brain and behaviour.